Device for coating strip material in continuous operation

ABSTRACT

There is disclosed a coating device for coating bands or ribbons with a coating material in continuous operation. The coating device comprises a main frame which mounts one or two deflector rollers for guiding and conveying the band or ribbon material to be coated. Coating is effected by a coating assembly which includes a fountain roll, a metering roll and an applicator roll which are disposed in axially parallel relationship and are adjustable relative one to another and relative to the band or ribbon to be coated as it is guided over one of the deflector rollers. The coating assembly is mounted on an auxiliary frame which is displaceable in the direction normal to the deflector roller over which the ribbon or band is guided. The auxiliary frame, in turn, is displaceable relative to the main frame for the purpose of making the rolls in the coating assembly conveniently accessible for cleaning or other servicing. There is further disclosed an installation including one or more coating devices in superimposition, each enclosed by an enclosure and drying and burning assemblies for purifying obnoxious or toxic pollutants entrained in the air passed through the enclosures of the coating devices before the air is discharged in the atmosphere.

i United States Patent 1191 Knodel et al.

[ Nov. 4, 1975 DEVICE FOR COATING STRIP MATERIAL 1 IN CONTINUOUS OPERATION [73] Assignee: Aluminium Norf GmbH, Neuss,

Germany [22] Filed: Aug. 23, 1974 [21] Appl. No.: 500,073

[30] Foreign Application Priority Data Aug. 29, 1973 Germany 2343431 52 US. Cl 118/224; 118/65 51 Int. c1. uosc 1/00 [58] Field of Search 118/61, 68, 223, 224, 246, ll8/249, 258, 259

[56] References Cited UNITED STATES PATENTS 2,610,411 9/1952 Steese 118/68 3,397,675 8/1968 De Ligt 118/258 3,793,051 2/1974 l-lerzhoff et al 118/61 Primary Examiner--Mervin Stein Assistant ExaminerSteven Hawkins Attorney, Agent, or Firml-lane, Baxley & Spiecens [57] ABSTRACT There is disclosed a coating device for coating bands or ribbons with a coating material in continuous operation. The coating device comprises a main frame which mounts one or two deflector rollers for guiding and conveying the band or ribbon material to be coated. Coating is effected by a coating assembly which includes a fountain roll, a metering roll and an applicator roll whichare disposed in axially parallel relationship and are adjustable relative one to another and relative to the band or ribbon to be coated as it is guided over one of the deflector rollers. The coating assembly is mounted on an auxiliary frame which is displaceable in the direction normal to the deflector roller over which the ribbon or band is guided. The auxiliary frame, in turn, is displaceable relative to the main frame for the purpose of making the rolls in the coating assembly conveniently accessible for cleaning or other servicing. There is further disclosed an installation including one or more coating devices in superimposition, each enclosed by an enclosure and drying and burning assemblies for purifying obnoxious or toxic pollutants entrained in the air passed through the enclosures of the coating devices before the air is discharged in the atmosphere.

11 Claims, 3 Drawing Figures sheet 1 on 3,916,824

US. Patent Nm 4, 1975 US. Patent Nov. 4, 1975 Sheet 2 of 3 3,916,824

U.S. Patent Nov. 4, 1975 Sheet 3 of3 3,916,824

DEVICE FOR COATING STRIP MATERIAL IN CONTINUOUS OPERATION The invention relates to a coating device for coating material in ribbon or band form in continuous operation and also to an installation which includes such coating devices and purifying means for removing pollutants entrained in the air used for accelerating drying of the coating material after application thereof before the air is discharged into the atmosphere.

BACKGROUND There are known coating devices of the general kind above-referred to which include one deflector roller or an upper and a lower deflector roller for guiding and conveying the band or ribbon material to be coated in continuous operation. In many instances the quality specifications with respect to the uniformity of the coating on the band or ribbon material is much greater for one side of the material than for the other side. In that case, the coating device for producing the high quality coating comprises a fountain roll for taking-up 0 pletion of the cleaning each roll must be detached from the auxiliary drive and re-attached to the drive of the device. All such decoupling, cleaning and recoupling obviously requires considerable time and labor and,

thus, a corresponding increase in costs.

The sealed enclosure of the installation, i.e., the enclosure in which the coating device proper is located, is connected with a suitable suction pump for sucking off the volatile components released by the coating material. Such suction pump and the conduits connected 0 therewith should be laid out so that a rapid air excoating from a source of supply, a metering roll and an applicator roll. Such coating device for producing the high quality coating is mounted on a frame structure so that its position can be adjusted relative to the respective deflector roller.

Installations for coating band or ribbon material frequently comprise two coating devices to permit rapid changing from one type of coating material to another; for instance, it may be desired to change the color or the coating material. If two or even more coating devices are provided, the devices are generally arranged in superimposition and mounted on a common frame structure detachable therefrom. With an installation of this type, the band or ribbon side to be coated with the high quality coating being generally the upwardly facing sides, it becomes necessary to effect a thorough cleaning of the rolls of each coating device before a change in color or coating material can be effected. As is evident, if the cleaning is not thoroughly made any residues of the previously used material will cause irregularities in the coating made after the cleaning of the coating device.

The need for such thorough cleaning of the coating devices is well understood in the art and to make such cleaning possible it is known to arrange the coating devices in the installation so that each of the coating de vices can be laterally withdrawn to assure that the coating devices are accessible for cleaning. The disadvantage of such laterally displacement as is now known is that considerable space is required for the coating device itself and such high space demand, in turn, greatly enlarges the total space required for the complete coating installation, i.e., including the assembly or assemblies needed for removing of pollutants that are unavoidably entrained in air passed through the coating devices. Virtually all coating materials contain volatile pollutants that are noxious and sometimes even toxic so that the air must be thoroughly purified before it can be discharged into the atmosphere. Arrangement of two superimposed coating devices, each coacting with a deflector roller makes it difficult to provide adequate accessibility to the fountain roll, metering roll and applicator roll of the coating devices for the purpose of thorough cleaning. In particular, considerable difficulties change is obtained to provide acceptable air conditions for the service personnel. The volume of air discharged from the space in which the coating is carried out can be fully fed to the drying assembly for drying of the coating material applied in the coating deviceonly if and when this volume of air does not exceed the air requirements of the drying assembly. The drying assembly is coupled in its downstream position with an afterburning device. The purpose of such after-burner is to assure reasonably complete elimination of noxious or toxic pollutants. The level of air purification is gener' ally controlled by strict codes which provide that the air discharged into the atmosphere cannot include more than a definite maximal percentage of pollutants.

To hold the operational costs of such after-burner assemblies as low as possible, efforts have been made to assure that the total volume of discharged air is reduced to an absolute minimum. To obtain optimal operational conditions for the installation it is advantageous that the total volume of air discharge can be processed in one after-burner assembly. However, such processing of the total air volume presupposes that the volume of air is discharged from the enclosure including one or more coating device can be fed to a drying assembly. This is only possible if the enclosed and sealed space for the coating devices, i.e., the overall dimensions of the enclosures for the coating devices is already at a minimum.

THE INVENTION It is a broad object of the invention to provide a novel and improved coating device of the general kind above referred to in which the enclosure for the coating device and the coating device itself are reduced to minimal dimensions while at the same time obtaining maximal accessibility of the coating device for cleaning and other servicing.

Another object of the invention is to provide a novel and improved installation so arranged that the air flow which, after passing through enclosures for the coating device or devices has entrained therein pollutants, is limited to a volume of air which can be purified at optimal conditions.

SUMMARY OF THE INVENTION The afore-pointed out objects, features and advantages and other objects, features and advantages which will be pointed out hereinafter are obtained by providing a coating device including a main frame structure, an auxiliary frame structure and a coating applicating assembly. The auxiliary frame structure supports the applicating assembly so that the same is displaceable in the direction normal to the path of the band or ribbon to be coated and is, in turn, supported by the main frame structure so that it can be displaced relative to said frame structure and also be detached therefrom. As a result, the over-all dimensions of the enclosure for the coating device can be selected so that the volume of air which must be passed through the enclosure during the coating operation can be held within limits which permit purification of the discharged air under optimal conditions and thus the volume of air continuously sucked out from the enclosure during a coating operation remains continuously at a rate which allows the use of economically acceptable after-burner assemblies; The discharge openings in the enclosures now need to be provided lengthwise of the bottom of the enclosure extending rows while heretofore additional crosswise extending air discharge openings were required.

The installation according to the invention further provides optimal accessibility of the coating devices proper so that servicing thereof, especially if, for instance, change in the color of the coating material is to be effected, can be carried out without considerable loss of time and without likelihood of insufficient cleaning of the rolls and other components of the coating device that need cleaning in case of change in the coating material.

After withdrawal of a coating device into the servicing position by a suitable power drive such as a servo system, the service personnel can clean or otherwise service the rolls of the coating devices while the rolls continue to rotate, as it is necessary for thorough cleaning and to effect such cleaning without first disconnecting the rollers from their operational drive means.

More specifically, the thorough cleaning of the rolls and other parts of the coating devices can be effected as sufficient space is available in a coating device according to the invention between the coating devices proper and the deflector roller over which the band or ribbon to be coated is guided during coating. Heretofore it was necessary for this purpose to effect timeconsuming and complex lateral withdrawal or complete detachment of the coating device by means of a hoist. Such cleaning and other servicing of a coating device also results in avoidance of damage to the rolls which are comparatively expensive. Saving or reduction of the time required for cleaning the rolls of the coating device, and especially the applicator roll to effect rapid readying of the device in case of change in the color of the coating material or use of other coating materials, is of considerable economic significance, the more so as modern technique desires high conveying speeds for the band or ribbon to be coated. The importance of rapid readying of the coating device forre-start with a changed coating material is particularly important if comparatively small lots of bands or ribbon are to be coated. Obviously, the smaller the lot to be coated is,

i the more it becomes economically important to ready the entire installation for resuming operation with the changed coating material.

The invention also provides that the afore-referred to auxiliary frame structure is coupled to the main frame structure by means of clamping means which can be power operated, for instance by servo systems using hydraulic or air pressure.'The use of such clamping means rial in continuous operation;

4 permits locking of the auxiliary frame structure to the main frame structure without tendency to vibrate, and simultaneously makes it easy to release the auxiliary frame structure from the main frame structure.

More specifically, operation of the clamping means is effected according to the invention-by a power drive such as a cylinder-piston servo-system in which the connecting rod for the piston of the system mounts an angle lever mounting and operating clamping elements which are releasably engageable with complementary clamping elements on the auxiliary frame structure.

According to a further aspect of the invention, the auxiliary frame structure can be displayed relative to the main frame structure by a servo-system or other power drive which is mounted on the main frame structure. By operating this system, the. auxiliary frame structure and with it the coating assembly supported on the same can be automatically detached from the main frame structure thereby obtaining clear space which is amply sufficient to carry out a thorough cleaning operation of the entire coating device without difficulty.

The air discharge and purifying parts and conduits which are disposed laterally of the main frame structure and the auxiliary frame structure can be used for immediate sucking out of air containing volatile pollutants or contaminants as may be released during a cleaning operation. i

To permit continuous operation even during change of the coating material, the invention also provides that several coating devices are disposed each in a separate enclosure and in superimposition. These enclosed coating devices are connected with a common drying assembly and an after-burner. assembly downstream of the drying assembly. The total discharge of contaminated air from the enclosures is fed to the drying assembly and the burner assembly by means of a suitable suction pump. Since the volume of air discharged from the enclosures in which the coating is carried out does not exceed the volume of air which can be accepted by the drying assembly, the total volume of air which contains a comparatively low amount of pollutants can be safely fed to the drying assembly. Additional content of pollutant as may be released in the drying assembly can subsequently be removed in the-after-bumer assembly. As a result, an additional after-burner assembly for the air discharged from the space in which coating is ef fected is thus avoided.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawing, preferred embodiments of the invention are shown by way of illustration and not by way of limitation.

In the drawing:

FIG. 1 is a diagrammatic elevational view of a coating device for coating both sides of a band or ribbon mate- FIG. 2 is a simplified plan view of FIG. 1; and FIG. 3 is a diagrammatic elevational view of an installation including coating devices according to FIG. I disposed in superimposition for simultaneously or singly coatingribbons or bands and further including an air-purifying device.

DETAILED DESCRIPTION OF THE DRAWING Referring now to the figures in greater detail, and first to FIG. 1, the coating device exemplified in this figure comprises a mainframe structure 1 and an auxiliary frame structure 2. These frame structures mount separate coating devices 3 and 4.

The main frame 1 further mounts two rotary deflector rollers 5 and 6 which serve to guide and convey a band or ribbon 7 to be coated. The auxiliary frame structure 2 mounts coating device 4 which is slidable relative to this frame structure by means of a guide slide 8. The coating device 4 is designed for coating the top or exposed side of band or ribbon 7 while coating device 3 serves for coating or otherwise treating the back side of the band or ribbon. The coating material may be any material suitable for the purpose, such as a dye, paint, lacquer, liquefied plastic, etc. Both coating devices are substantially alike as to their functional arrangement except that the coating device 4 being designed for coating the topside of the band or ribbon must be and is designed to effect a coating which satisfies high demand for uniformity, accuracy and similar requirements. Accordingly, device 4 includes various adjustment and control means which are not required for coating device 3 if, as is frequently the case, the demands on the quality of the coating on the back side are much lower than those for the coating of the top side.

Coating device 4 comprises an applicator roll 9, a fountain roll for taking-up the coating material to be applied, and a metering roll 11. Similarly, the coating device 3 comprises an applicator roll 9, a fountain roll 10 and a metering roll 11.

- In addition to the afore-listed rolls, coating device 4 comprises guide carriers or slides l2, l3 and 14, each supporting one of the rolls. The positions of these slides and thus of the rolls relative one to another are adjustable by fine setting means such as hand wheels 18, 19 and 20 so that the cylindrical wall of the rolls are in coacting engagement, or in other words, the peripheral surface of one of the rolls rolls off the peripheral surface of the adjacent roll or rolls. Each of the three rolls is drivingly coupled by couplings 15, 16 and 17, respectively, with a separate drive means 21 (see FIG. 2).

Moreover, the entire coating device 4 can be by means of guide slide 8 which carries the guide slides 12, 13 and 14, displaced relative to the upper deflector roller 5 by means of a cylinder-piston-servo means 22 having a short stroke until stopped by an adjustable stop 37. The servo means 22 can be driven hydraulically or by air pressure. The purpose of the servo means is to move the coating device clear of the band when and while joints of lengths of band or ribbon pass the coating device, as such joints generally are somewhat thicker than the normal thickness of the band. After the passage of such joint the coating device is returned into its coating position. Control of the servo means can be automatically effected, for instance, by means of photocells or other control means conventional readily available in the market. The application of coating material is effected by transfer of material taken up by fountain roll 10 to metering roll 11, and finally, to applicator roll 9, which applies the coating material upon the upward facing band or ribbon 7 as the same is being guided and conveyed by deflector roll 5.

If the coating material is to be changed, for instance if material having a different color is to be used, rolls 9, l0 and 11 of coating device 4 and possibly other components thereof must be very carefully cleaned to prevent faulty coating such as discoloration, spots, etc. For the purpose of such cleaning, the entire coating device 4 can be displaced in the lengthwise direction of the coating device, that is, normal to the axis of roller 5, to

a position in which there is free and convenient access 6 to the device for cleaning the rolls and possibly other components.

To effect such convenient displacement of the coating device into and out of its operational position for the purpose of cleaning, the auxiliary frame structure 2 is displaceable on a guide means 23 which is mounted on the base or inserted into the base of auxiliary frame structure 2. Displacement of frame structure 2 is effected by suitable adjustment means such as a hydraulically operated servo-piston system 24. This servosystem is fixedly secured to main frame structure 1 and the piston rod 25 of system 24 can be moved into engagement with protrusions such as studs 26 on frame structure 2. Accordingly, by operating the servo system 24, its piston rod 25 can be used to move coating device 4 via auxiliary frame structure 2 into and out of its operational position.

Setting of auxiliary frame structure 2 and coating device 4 relative to deflector roller 5 is effected in the following manner: First, piston rod 25 of servo system 24 is operated to couple frame structure 2 with frame structure 1. As a result, there is a force-transmitting connection between both frame structures by means of a further power operated, for instance, hydraulically by a cylinder-piston servo system 27. The piston 28 of this system mounts a linkage 29 and 30 to which are hinged locking elements 31 and 32 which, upon operation of servo-system 27 effect coupling with coupling noses such as discs 33 and 34 on auxiliary frame structure 2.

After connection of frame structure 2 to frame structure l, fine adjustment of rolls 9, 10 and 11 is efiected by hand wheels l8, l9 and 20, respectively.

Operation of coating device 3 is essentially the same as that of coating device 4, except that adjustment and clearing of rolls 9, l0 and 11' is not or only rarely required since the quality demands on the coating of the bottom side of bandor ribbon are much less on the coating of the top side as previously explained.

Turning now to FIGS. 2 and 3, these figures show application of the invention to an installation including two or more coating devices so that minimum space requirement is combined with convenient servicing of the coating devices as hereinbefore described. Furthermore, the installation due to the arrangement of coating devices according to the invention can be so designed that the air released during operation of the coating devices can be conveniently and thoroughly purified. Many types of coating materials such as certain paints, dyes, etc. contain volatile components which are released during application and drying and are obnoxious or even toxic. Accordingly, purification of the discharged airis highly necessary and often required by local codes.

FIGS. 2 and 3 show diagrammatically an installation which fully utilizes the advantages of coating devices according to the invention. As it is shown in these figures, each of the two coating devices is enclosed in a separate sealed-off enclosure 37 and 37', respectively. The outside dimensions of these enclosures can be conveniently selected in accordance with the minimal space requirements of the main frame structure and the auxiliary frame structure of coating device 4. There are shown two coating devices disposed in superimposition and enclosed by enclosures 37 and 37, respectively. Of course, there may be several enclosures side-by-side on the same level. More than two coating devices and enclosures therefor can be superimposed. Drying air after being drawn through theenclosures for the coating devices is fed via discharge ducts to air-purifying assemblies as it is shown in FIG. 3 to the right of the coating devices. Ducts 35 are preferably arranged parallel to each other as it is shown in FIG. 3 and also parallel to the bottom of the enclosures, thereby reducing the required space to a minimum. Moreover, due to such arrangement, the required air volume can be maintained so that the discharge of the total air volume from enclosures 37 and 37 and the feed of this discharged air to the air purifying assemblies is made readily possible.

There is provided for each of the enclosures 37 and 37' an air-purifying assembly. The assembly for coacting with enclosure 37 is fully shown and described, but the assembly for enclosure 37' is only partly shown as the two assemblies are alike and function in the same manner.

The assembly coacting with enclosure 37 comprises a drying device 38 which, as shown, may be divided into several parts: a heat-exchanger 39, burners 40, one for each part of the drying device, an after-burner 41, a suction pump 42, and suction pumps 43, one for each burner 40. All these components arepresumed to be of conventional design. The air used in enclosure 37 during the coating operations, which as previously becomes contaminated during and due to the coacting operations, is sucked out by means of suction pump 42 and fed via conduit 35 and heat-exchanger 39 to drying device 38. The drying process in device 38 removes most of the contaminants in the air. The air is then returned to heat-exchanger 39 and from this exchanger to suction pump 42 through which it is discharged into the atmosphere. To assure still further purification of the air, the after-burner 41 may be interposed between the drying device and the heat exchanger. It has been found that reheating of the air while being dried in drying device 38 is necessary or, at least, desirable. For this purpose, part of the air in the drying device is sucked out by suction pumps 43 and exposed to the heat of burners which causes not only reheating of the air but also the burning of pollutants or contaminants still contained in the air. The sucked-off air is returned into the drying device to be discharged therefrom into the atmosphere together with the air remaining in the drying device. Dotted arrowheads indicate the feed of air from the enclosure 38 into the drying device and solid arrowheads indicate the flow of part of the air as caused by suction pumps 43.

' As several coating devices are arranged in superimposition in FIG. 3 and each one is enclosed in an enclosure there is no undesirable delay in the carrying out of a coating operation in one of the coating devices when a change in the coating material is effected in another coating device. In other words, all coating devices can be kept in operation except the one in which a change in the coating material is made.

In case two superimposed coating devices are used for coating the top side of bands or ribbons within the same installation vibrations may occur when one of the coating devices is withdrawn for cleaning purposes or change in the coating material. The result of such vibrations would be irregularities in the coating as effected by the second coating device. This danger is avoided by providing separation of the coating devices by enclosures as it is shown in FIG. 3.

While the invention has been described in detail with respect to certain now preferred examples and embodiments of the invention, it will be understood by those 8 skilled in the art, after understanding the invention, that various'change s and modifications may be made without departing from the spirit and scope of the invention, and it is-intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed is:

l. A coating device for coating bands with a coating material in continuous operation, said coating device comprising in combination:

a main stationary mounted frame structure;

rotary guide means for guiding band material to be coated, said guide means including at least one deflector roller and being mounted on said main frame structure;

a coating assembly for coating the side of the band outwardly facing on said roller, said assembly including a fountain roll for supplying coating material, a metering roll and an applicator roll disposed in axially parallel relationship one with the other and the deflector roller;

an auxiliary frame structure supporting said coating assembly, said auxiliary frame structure including guide means for slidably guiding said coating assembly as a unit in the direction normal to the rotary axis of the deflector roller for selecting varying positions of said assembly relative to said roller;

guide means on said main frame structure slidably supporting said auxiliary frame structure for selectively displacing the same in the direction normal to the axis as a unit relative to the main structure and thus relative to the deflector roller;

drive means for moving said auxiliary frame structure into a predetermined position relative to the main frame structure; and

locking means coacting with said auxiliary frame structure for releasably locking the same to the main frame structure.

2. A coating device in accordance with claim 1 wherein said drive means comprise a cylinder-piston servo means, the cylinder of said means being mounted on said main frame structure and the piston of said servo means being drivingly coupled with said auxiliary frame structure for displacing the same relative to the main frame structure by activating the servo means.

3. A coating device in accordance with claim 1 wherein said locking means comprise coating clamping members on the main frame structure and the auxiliary frame structure for releasably clamping the auxiliary frame structure in a selected position to the main frame structure.

4. A coating device in accordance with claim 3 wherein said clamping means comprise on one of the frame structures cylinder-piston servo means and linkage means coupled to the piston for controlling the position thereof in the cylinder and on the other frame structure retention means engaged with the linkage means in a predetermined position of said piston.

5. An installation for coating bands in continous operation, said installation comprising in combination:

a plurality of coating devices as defined in claim 1;

a separate enclosure for each of said coating devices;

and

an air purifying assembly for each of said enclosures,

for removing pollutants released by the coating material and entrained in air, each of said assemblies comprising pump means, burner means for burning combustible pollutants entrained in air, drying means and conduits interconnecting each of said 8. An installation in accordance with claim 7 wherein said conduits are disposed in mutually parallel relationship with and between the superimposed enclosures.

9. An installation in accordance with claim 7 and comprising heat-exchanger means for each of said assemblies, each of said heat-exchanger means being included in the respective conduits.

10. A coating device according to claim 1 and comprising second drive means for displacing said coating assembly relative to the auxiliary frame structure and thus relative to the selector roller.

11. A coating device according to claim 1 wherein said guide means on the auxiliary frame structure and on the main frame structure are linear guide means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTlON Patent NO. 3,916,824 Dated November 4, 1975 Peter Knodel et a1. Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet item I73] Should read Assignee: Aluminium Norf GmbH, Neuss Germany and Werner G Pfleiderer Stuttgart,

Germany Signed and Sealed this twenty-fourth D21) Of February 1976 [SEAL] Arrest."

RUTH C. MASON C. MARSHALL DANN Arresting Officer I (mnmissinm'r nj'lara'nrs and Trademarks 

1. A coating device for coating bands with a coating material in continuous operation, said coating device comprising in combination: a main stationary mounted frame structure; rotary guide means for guiding band material to be coated, said guide means including at least one deflector roller and being mounted on said main frame structure; a coating assembly for coating the side of the band outwardly facing on said roller, said assembly including a fountain roll for supplying coating material, a metering roll and an applicator roll disposed in axially parallel relationship one with the other and the deflector roller; an auxiliary frame structure supporting said coating assembly, said auxiliary frame structure including guide means for slidably guiding said coating assembly as a unit in the direction normal to the rotary axis of the deflector roller for selecting varying positions of said assembly relative to said roller; guide means on said main frame structure slidably supporting said auxiliary frame structure for selectively displacing the same in the direction normal to the axis as a unit relative to the main structure and thus relative to the deflector roller; drive means for moving said auxiliary frame structure into a predetermined position relative to the main frame structure; and locking means coacting with said auxiliary frame structure for releasably locking the same to the main frame structure.
 2. A coating device in accordance with claim 1 wherein said drive means comprise a cylinder-piston servo means, the cylinder of said means being mounted on said main frame structure and the piston of said servo means being drivingly coupled with said auxiliary frame structure for displacing the same relative to the main frame structure by activating the servo means.
 3. A coating device in accordance with claim 1 wherein said locking means comprise coating clamping members on the main frame structure and the auxiliary frame structure for releasably clamping the auxiliary frame structure in a selected position to the main frame structure.
 4. A coating device in accordance with claim 3 wherein said clamping means comprise on one of the frame structures cylinder-piston servo means and linkage means coupled to the piston for controlling the position thereof in the cylinder and on the other frame structure retention means engaged with the linkage means in a predetermined position of said piston.
 5. An installation for coating bands in continous operation, said installation comprising in combination: a plurality of coating devices as defined in claim 1; a separate enclosure for each of said coating devices; and an air purifying assembly for each of said enclosures, for removing pollutants released by the coating material and entrained in air, each of said assemblies comprising pump means, burner means for burning combustible pollutants entrained in air, drying means and conduits interconnecting each of said enclosures with said pump means, said drying means and said burner means for forcing air flow sequentially through the respective enclosure, burner means and drying means thereby purifying the air and discharge means for discharging the purified air for the enclosures into the atmosphere.
 6. An installation in accordance with claim 5 and comprising in each of said assemblies after-burner means interposed between said drying means and discharge means for discharging air into the atmosphere.
 7. An installation in accordance with claim 5 wherein said enclosures are disposed in superimposition.
 8. An installation in accordance with claim 7 wherein said conduits are disposed in mutually parallel relationship with and between the superimposed enclosures.
 9. An installation in accordance with claim 7 and comprising heat-exchanger means for each of said assemblies, each of said heat-exchanger means being included in the respective conduits.
 10. A coating device according to claim 1 and comprising second drive means for displacing said coating assembly relative to the auxiliary frame structure and thus relative to the selector roller.
 11. A coating device according to claim 1 wherein said guide means on the auxiliary frame structure and on the main frame structure are linear guide means. 